﻿using System;
using System.Configuration;
using System.Data;
using System.Data.OleDb;
using System.Collections;

namespace MySite.SQLHelper
{
    /// <summary>
    /// The SqlHelper class is intended to encapsulate high performance, 
    /// scalable best practices for common uses of SqlClient.
    /// </summary>
    public abstract class OledbHelper
    {
        private static readonly log4net.ILog log = log4net.LogManager.GetLogger(System.Reflection.MethodBase.GetCurrentMethod().DeclaringType);
        
        //Database connection strings
        public static readonly string ConnectionStringCore = ConfigurationManager.ConnectionStrings["Core"].ConnectionString;

        public static OleDbConnection OlecdConn = new OleDbConnection(ConnectionStringCore);

        private static Hashtable parmCache = Hashtable.Synchronized(new Hashtable());

        /// <summary>
        /// Execute a SqlCommand (that returns no resultset) against the database specified in the connection string 
        /// using the provided parameters.
        /// </summary>
        /// <remarks>
        /// e.g.:  
        ///  int result = ExecuteNonQuery(connString, CommandType.StoredProcedure, "PublishOrders", new SqlParameter("@prodid", 24));
        /// </remarks>
        /// <param name="connectionString">a valid connection string for a SqlConnection</param>
        /// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
        /// <param name="commandText">the stored procedure name or T-SQL command</param>
        /// <param name="commandParameters">an array of SqlParamters used to execute the command</param>
        /// <returns>an int representing the number of rows affected by the command</returns>
        public static int ExecuteNonQuery(string connectionString, CommandType cmdType, string cmdText, params OleDbParameter[] commandParameters)
        {
            log.DebugFormat("连接字符串:{0}", connectionString);
            log.DebugFormat("CMD类型:{0}", cmdType);
            log.DebugFormat("执行命令:{0}", cmdText);
            Log(commandParameters);

            OleDbCommand cmd = new OleDbCommand();

            using (OleDbConnection conn = new OleDbConnection(connectionString))
            {
                PrepareCommand(cmd, conn, null, cmdType, cmdText, commandParameters);
                int val = cmd.ExecuteNonQuery();
                cmd.Parameters.Clear();

                log.DebugFormat("受影响行数:{0}", val);
                return val;
            }
        }

        /// <summary>
        /// Execute a SqlCommand (that returns no resultset) against an existing database connection 
        /// using the provided parameters.
        /// </summary>
        /// <remarks>
        /// e.g.:  
        ///  int result = ExecuteNonQuery(connString, CommandType.StoredProcedure, "PublishOrders", new SqlParameter("@prodid", 24));
        /// </remarks>
        /// <param name="conn">an existing database connection</param>
        /// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
        /// <param name="commandText">the stored procedure name or T-SQL command</param>
        /// <param name="commandParameters">an array of SqlParamters used to execute the command</param>
        /// <returns>an int representing the number of rows affected by the command</returns>
        public static int ExecuteNonQuery(OleDbConnection connection, CommandType cmdType, string cmdText, params OleDbParameter[] commandParameters)
        {
            log.DebugFormat("连接字符串:{0}", connection.ConnectionString);
            log.DebugFormat("CMD类型:{0}", cmdType);
            log.DebugFormat("执行命令:{0}", cmdText);
            Log(commandParameters);

            OleDbCommand cmd = new OleDbCommand();

            PrepareCommand(cmd, connection, null, cmdType, cmdText, commandParameters);
            int val = cmd.ExecuteNonQuery();
            cmd.Parameters.Clear();
            log.DebugFormat("受影响行数:{0}", val);
            return val;
        }

        /// <summary>
        /// Execute a SqlCommand (that returns no resultset) using an existing SQL Transaction 
        /// using the provided parameters.
        /// </summary>
        /// <remarks>
        /// e.g.:  
        ///  int result = ExecuteNonQuery(connString, CommandType.StoredProcedure, "PublishOrders", new SqlParameter("@prodid", 24));
        /// </remarks>
        /// <param name="trans">an existing sql transaction</param>
        /// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
        /// <param name="commandText">the stored procedure name or T-SQL command</param>
        /// <param name="commandParameters">an array of SqlParamters used to execute the command</param>
        /// <returns>an int representing the number of rows affected by the command</returns>
        public static int ExecuteNonQuery(OleDbTransaction trans, CommandType cmdType, string cmdText, params OleDbParameter[] commandParameters)
        {
            log.DebugFormat("连接字符串:{0}", trans.Connection.ConnectionString);
            log.DebugFormat("CMD类型:{0}", cmdType);
            log.DebugFormat("执行命令:{0}", cmdText);
            Log(commandParameters);

            OleDbCommand cmd = new OleDbCommand();
            PrepareCommand(cmd, trans.Connection, trans, cmdType, cmdText, commandParameters);
            int val = cmd.ExecuteNonQuery();
            cmd.Parameters.Clear();
            log.DebugFormat("受影响行数:{0}", val);
            return val;
        }

        /// <summary>
        /// Execute a SqlCommand that returns a resultset against the database specified in the connection string 
        /// using the provided parameters.
        /// </summary>
        /// <remarks>
        /// e.g.:  
        ///  SqlDataReader r = ExecuteReader(connString, CommandType.StoredProcedure, "PublishOrders", new SqlParameter("@prodid", 24));
        /// </remarks>
        /// <param name="connectionString">a valid connection string for a SqlConnection</param>
        /// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
        /// <param name="commandText">the stored procedure name or T-SQL command</param>
        /// <param name="commandParameters">an array of SqlParamters used to execute the command</param>
        /// <returns>A SqlDataReader containing the results</returns>
        public static OleDbDataReader ExecuteReader(string connectionString, CommandType cmdType, string cmdText, params OleDbParameter[] commandParameters)
        {
            log.DebugFormat("连接字符串:{0}", connectionString);
            log.DebugFormat("CMD类型:{0}", cmdType);
            log.DebugFormat("执行命令:{0}", cmdText);
            Log(commandParameters);

            OleDbCommand cmd = new OleDbCommand();
            OleDbConnection conn = new OleDbConnection(connectionString);

            // we use a try/catch here because if the method throws an exception we want to 
            // close the connection throw code, because no datareader will exist, hence the 
            // commandBehaviour.CloseConnection will not work
            try
            {
                PrepareCommand(cmd, conn, null, cmdType, cmdText, commandParameters);
                OleDbDataReader rdr = cmd.ExecuteReader(CommandBehavior.CloseConnection);
                cmd.Parameters.Clear();
                log.DebugFormat("返回结果:{0}", rdr);
                return rdr;
            }
            catch(Exception e)
            {
                conn.Close();
                log.Error(conn, e);
                throw;
            }
        }

        /// <summary>
        /// Execute a sqlcommand that returns a dataset.
        /// </summary>
        /// <param name="connectionString">a volid connection string for a sqlconnection</param>
        /// <param name="cmdType">the commandtype</param>
        /// <param name="commandParameters">an array of sqlparameters used to execute the command</param>
        /// <returns>a dataset containing the results</returns>
        public static DataSet ExecuteQuery(string connectionString, CommandType cmdType, string cmdText, params OleDbParameter[] commandParameters)
        {
            log.DebugFormat("连接字符串:{0}", connectionString);
            log.DebugFormat("CMD类型:{0}", cmdType);
            log.DebugFormat("执行命令:{0}", cmdText);
            Log(commandParameters);

            DataSet ds = null;

            OleDbCommand cmd = new OleDbCommand();
            OleDbConnection conn = new OleDbConnection(connectionString);

            // we use a try/catch here because if the method throws an exception we want to 
            // close the connection throw code, because no datareader will exist, hence the 
            // commandBehaviour.CloseConnection will not work
            try
            {
                PrepareCommand(cmd, conn, null, cmdType, cmdText, commandParameters);
                OleDbDataAdapter sda = new OleDbDataAdapter();
                sda.SelectCommand = cmd;
                ds = new DataSet();
                sda.Fill(ds);
                cmd.Parameters.Clear();
                log.DebugFormat("返回结果:{0}", ds);
            }
            catch (Exception e)
            {
                log.Error(connectionString, e);
                throw;
            }
            finally
            {
                conn.Close();
                conn.Dispose();
            }

            return ds;
        }

        /// <summary>
        /// Execute a SqlCommand that returns the first column of the first record against the database specified in the connection string 
        /// using the provided parameters.
        /// </summary>
        /// <remarks>
        /// e.g.:  
        ///  Object obj = ExecuteScalar(connString, CommandType.StoredProcedure, "PublishOrders", new SqlParameter("@prodid", 24));
        /// </remarks>
        /// <param name="connectionString">a valid connection string for a SqlConnection</param>
        /// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
        /// <param name="commandText">the stored procedure name or T-SQL command</param>
        /// <param name="commandParameters">an array of SqlParamters used to execute the command</param>
        /// <returns>An object that should be converted to the expected type using Convert.To{Type}</returns>
        public static object ExecuteScalar(string connectionString, CommandType cmdType, string cmdText, params OleDbParameter[] commandParameters)
        {
            log.DebugFormat("连接字符串:{0}", connectionString);
            log.DebugFormat("CMD类型:{0}", cmdType);
            log.DebugFormat("执行命令:{0}", cmdText);
            Log(commandParameters);

            OleDbCommand cmd = new OleDbCommand();

            using (OleDbConnection connection = new OleDbConnection(connectionString))
            {
                PrepareCommand(cmd, connection, null, cmdType, cmdText, commandParameters);
                object val = cmd.ExecuteScalar();
                cmd.Parameters.Clear();
                log.DebugFormat("返回结果:{0}", val);
                return val;
            }
        }

        /// <summary>
        /// Execute a SqlCommand that returns the first column of the first record against an existing database connection 
        /// using the provided parameters.
        /// </summary>
        /// <remarks>
        /// e.g.:  
        ///  Object obj = ExecuteScalar(connString, CommandType.StoredProcedure, "PublishOrders", new SqlParameter("@prodid", 24));
        /// </remarks>
        /// <param name="conn">an existing database connection</param>
        /// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
        /// <param name="commandText">the stored procedure name or T-SQL command</param>
        /// <param name="commandParameters">an array of SqlParamters used to execute the command</param>
        /// <returns>An object that should be converted to the expected type using Convert.To{Type}</returns>
        public static object ExecuteScalar(OleDbConnection connection, CommandType cmdType, string cmdText, params OleDbParameter[] commandParameters)
        {
            log.DebugFormat("连接字符串:{0}", connection.ConnectionString);
            log.DebugFormat("CMD类型:{0}", cmdType);
            log.DebugFormat("执行命令:{0}", cmdText);
            Log(commandParameters);

            OleDbCommand cmd = new OleDbCommand();

            PrepareCommand(cmd, connection, null, cmdType, cmdText, commandParameters);
            object val = cmd.ExecuteScalar();
            cmd.Parameters.Clear();
            log.DebugFormat("返回结果:{0}", val);
            return val;
        }

        /// <summary>
        /// add parameter array to the cache
        /// </summary>
        /// <param name="cacheKey">Key to the parameter cache</param>
        /// <param name="cmdParms">an array of SqlParamters to be cached</param>
        public static void CacheParameters(string cacheKey, params OleDbParameter[] commandParameters)
        {
            log.DebugFormat("缓存Key:{0}", cacheKey);
            Log(commandParameters);
            parmCache[cacheKey] = commandParameters;
        }

        /// <summary>
        /// Retrieve cached parameters
        /// </summary>
        /// <param name="cacheKey">key used to lookup parameters</param>
        /// <returns>Cached SqlParamters array</returns>
        public static OleDbParameter[] GetCachedParameters(string cacheKey)
        {
            log.DebugFormat("缓存Key:{0}", cacheKey);
            OleDbParameter[] cachedParms = (OleDbParameter[])parmCache[cacheKey];

            if (cachedParms == null)
                return null;

            OleDbParameter[] clonedParms = new OleDbParameter[cachedParms.Length];

            for (int i = 0, j = cachedParms.Length; i < j; i++)
                clonedParms[i] = (OleDbParameter)((ICloneable)cachedParms[i]).Clone();

            return clonedParms;
        }

        /// <summary>
        /// Prepare a command for execution
        /// </summary>
        /// <param name="cmd">SqlCommand object</param>
        /// <param name="conn">SqlConnection object</param>
        /// <param name="trans">SqlTransaction object</param>
        /// <param name="cmdType">Cmd type e.g. stored procedure or text</param>
        /// <param name="cmdText">Command text, e.g. Select * from Products</param>
        /// <param name="cmdParms">SqlParameters to use in the command</param>
        private static void PrepareCommand(OleDbCommand cmd, OleDbConnection conn, OleDbTransaction trans, CommandType cmdType, string cmdText, OleDbParameter[] cmdParms)
        {
            log.DebugFormat("连接字符串:{0}", conn.ConnectionString);
            log.DebugFormat("CMD类型:{0}", cmdType);
            log.DebugFormat("执行命令:{0}", cmdText);
            Log(cmdParms);

            if (conn.State != ConnectionState.Open)
                conn.Open();

            cmd.Connection = conn;
            cmd.CommandText = cmdText;

            if (trans != null)
                cmd.Transaction = trans;

            cmd.CommandType = cmdType;

            if (cmdParms != null)
            {
                foreach (OleDbParameter parm in cmdParms)
                    cmd.Parameters.Add(parm);
            }
        }

        /// <summary>
        /// 用于记录日志输出
        /// </summary>
        /// <param name="paras"></param>
        private static void Log(OleDbParameter[] paras)
        {
            if (paras != null)
            {
                foreach (OleDbParameter para in paras)
                {
                    log.DebugFormat("参数:{0},值:{1}", para.ParameterName, para.Value);
                }
            }
        }

        public static bool CheckTable(string tableName)
        {
            OlecdConn = new OleDbConnection(ConnectionStringCore);
            using (OleDbConnection connection = new OleDbConnection(ConnectionStringCore))
            {
                connection.Open();
                DataTable schemaTable = connection.GetOleDbSchemaTable(
                    OleDbSchemaGuid.Tables,
                    new object[] { null, null, null, "TABLE" });

                foreach (DataRow dr in schemaTable.Rows)
                {
                    if (Convert.ToString(dr[0]) == tableName || Convert.ToString(dr[1]) == tableName || Convert.ToString(dr[2]) == tableName)
                    {
                        connection.Close();
                        return true;
                    }
                }
            }
            
            return false;
                
        }

    }
}